Float valve for fuel systems



1949 D. SAMIRAN 2,491,521

FLOAT VALVE FOR FUEL SYSTEMS Filed Feb. 5, 1946 2 She'ets-Sheet 1 W /Zz1949 D. SAMIRAN FLOAT VALVE FOR FUEL SYSTEMS 2 Sheets-Sheet 2 Filed Feb.5, 1946 Patented Dec. 20, 1949 UNITED STATES PATENT OFFICE (Grantedunder the act of March 3, 1883, as amended April 30, 1928; 370 O. G.757) 3 Claims.

The invention described herein may be manufactured and used by or forthe Government for governmental purposes without payment to me of anyroyalty thereon.

This invention relates to float valves and has particular reference to avalve for preventing additional fluid entering a tank when it is alreadyfilled to a predetermined level.

An object of the invention is to provide a valve of this kind whichdepends on the pressure of the incoming fluid to operate it to a closedposition, a small auxiliary valve only being operated by a float todirect fluid under pressure to a main valve closing means.

Valves of this character are being employed in fuel tanks for aircraftand such tanks, due to space limitations, may in some cases preferablybe replenished from the top downward and in other cases from the bottomupward, and it therefore is another object of the invention to soconstruct and arrange the valve that it may be used either end up if sodesired.

Other objects and advantages will become apparent as the invention isfurther described, reference being made to the drawings, wherein:

Fig. 1 is a vertical axial section through a float valve made accordingto my invention showing the float midway of its possible travel, inwhich position the valve is closed, other positions of the float beingshown in phantom.

Fig. 2 shows the float actuated auxiliary valve closed as in Fig. 1 butshown to an enlarged scale.

Fig. 3 is a view like Fig. 2 except that the auxiliary valve is in oneof its open positions.

Fig. 4 is a view like Fig. 3 except that the auxiliary valve is in theother of its open positions.

Like reference characters refer to like parts throughout the drawings.

The float valve selected for illustrative purposes has its housing intwo parts It and !2 with a diaphragm l4 clamped therebetween by means ofscrew (not shown). A hose connection It and a central hub 18 areintegral with the upper part It. An annular space 23 surrounds the hub18 and has a series of radial openings 22 connecting the annular space25] to the outside of the housing. A main valve seat 2! is formed on thelower end of the hub 18.

The diaphragm I4 is held between washers 23 and 26, while a main valveseat washer 28 is held between washer 26 and a flange 3!]. Flange 33 iscarried on an externally threaded hollow hub 32 and a nut 34 clampsparts 24, M, 26, 28, and 30 together. The space 33 is separated from theannular space 20 when the main valve seat washer 23 is on its seat 2|,as shown in Fig. 1.

Within the hollow hub 32 is a flanged cup 36 and surrounding this cup isa spring 38, the lower end of which rests on the housing I2 and theupper end of which bears against the underside of the flange of the cup.The spring 38 is under sufiicient stress to press the main valve seatwasher 28 lightly against the seat 2| when the valve is not operating.In operation, however, the main valve seat washer 28 seats only when thepressure in the space 33 above the main valve and the pressure in thespace 39 below the main valve is equalized. In that case the pressure,acting over a much greater area in the chamber 39 than in the space 33,is suflicient to hold the main valve seat washer 28 on its seat 2|. Themain valve assembly may be broadly designated by the numeral 4|.

Formed within the hollow hub 32 is a check valve seat 43 against which acheck valve seat washer 42 is held by a sprin M. A depression in thebottom of the cup 36 holds the spring 44 concentrically positioned. Asmall port 46 in the closed end of the hollow hub 32 connects the space33 above the main seat washer 28 to the space 39 below it when the checkvalve seat washer 42 is off its seat 40. Holes 43 and 5!] through thecheck valve seat washer 42 and through the bottom of the cup 36respectively permit fluid to pass through from the space 33 to the space39 when the check valve seat washer 42 is off its seat Mi. The smallspring 44 is of suflicient strength to hold the check valve seat washer42 on its seat it lightly, but cannot hold the check valve closedagainst the pressure in the space 33 except when sufflcient pressurealso exists in the chamber 39. The check valve may be broadly designatedby the numeral 5|.

In the bottom of the lower housing part i2 is a piston valve, which isshown to a larger scale in Figs. 2, 3, and 4. The piston valve comprisesa bushing 52 which is closed at the upper end and press fitted into thehousin and a lap fitted piston 54 which is slidable in the bushing. Anaxial passageway 56 extends from one end into the piston 54 and anannular groove 58 surrounds the piston. Radial holes 63 extend throughthe head of the bushing for establishing communication between thechamber 39 and the groove 58, and radial holes 62 connect the groove 58to the axial passageway 56. Other radial holes 64 connect the axialpassageway to the float chamber 66. The assembled bushing 52 and piston54 and their several passageways comprise the piston valve which may bebroadly designated by the numeral 6!.

A protective cover 68 surrounds the float chamber 66 and is held on byscrews 73. Openings 12 connect the inside of the float chamber to thespace surrounding it. A float M preferably made of cork or similarmaterial is reinwith the plate 16 and is hinged by a pin 88to an car 86which depends from the housing part-l2.

Downward swinging of the float 14 is limited by contact with the screw90 while upward swinging is arrested by engagement of the end of thepiston 54 with the closed end of the bushing 52.

The operation of the valve is substantiallyas follows:

When the fuel is at the desired level in a tank equippd with my 'floatvalve, the valve will apbe'closedas' seen" in Fig. 2. Fuel "underpumppressuredn the space- 33' will pass through the midway zposition;wherebythe piston valve will' check valve 5! into the chambe 39 to keep themain-valve 4i o'losedv- When, however; the-level of 'the fuel in thetank drops 'until -the float assumes the position 92,- the' piston valve'61 will be'in one of its open positionsas-seen-inFig. 13. In'thisposition the piston valvefil will=drain fuel from thechamber39-faster-than+it -can-be supplied through the cheek *valve5l,-wh'ereupon the main valve M will open andallow the fuel-level torisein the tank until the float again assumes the positionseen-in Fig.'1, lu -which position the piston valvefil and the-rnain-valve M-are-c1osed-.-

When-the-valve is-beingeused in the invertedposition and the" fuel inthe tank 1 has dropped below the desired level, the float will-bearrested in the position fi thy-reason of the piston 54 -en-- countering-;the closed end of the bushing 52 seen in Fig. l andthe piston valvewill be open as shown. The -fluid under pressure in the space 39 againdrains from the'sp-ace 39 through thepiston veneer-faster than it canbereplenished through th'e check 'val'vel', whereupon the main valved!"opens; Fuel will then flow through the 7 main valveuntil the floatrisestothe level position at which the'pist'on"valve'will be closed asin-Fig. 2 and the main valve" will be closed thereby It willbe's'een"thatjwhether the device'is up right orinverted, wheneverthefloat M is in the horizontal 'orrnidw'aypos'ition' of'itstravel, themain valve 4! will be closed, and it should not open againex'ceptupori'the dropping of the float one "wayor the other "from thmidway position. It has been found, however, that whenthe pressurein'thespa'c'e'33' is being supplied by a pump which is considerablylower than the fuel level in' the tankj'and'pumping' is momentarilyinterruptedf the' syphoning eflect of the column of fluid between theta'nk andpump would, in the the chamber 39" and open themain valve 4!regardless' of themidwa'y" position'of the float M.

i-wm b 'apparent,therefore, that the function of the check valve 5| isto' make sure that a momentary'dr'op'in pressure in the space 33 willnot open the main" valve 4| when the float i4 is at" the midpoint valveclosing position.

Having described my invention, I claim:

1. Float controlled"valvemechanism comprising a main valve-adapted atits inlet side toreunder pressure to close said main valve, a passageway adapted to convey fluidunder pressure from the inlet side ofsaidmain valve to the inflow side of said pressure closing means, afloat actuated valve associated with said pressure closing means adaptedwhen opened to drain fluid from said pressure closing means faster thanit maybe renewed by Way of said passageway, and a float adapted, at itsnormal or medial position, to hold said float'actuated valve closed andabove or below said medial position to hold said float actuated valveopen, whereby said valve mechanism maybe used either in the upright orin the inverted position."

2. Float operated valve mechanism which comprises'a main valve seat, a.main valve closing disc having one side engageable-with said seat, fluid1 pressure actuated" means adapted to engage said--- disc with said seatagainst incoming fluid-under pressure, a leakage opening-through saiddisc in the path-of the incoming fluid for supplying fluid to saidpressure actuatedmeans for-operat ing said pressure' actuated-means forengagingsaid disc with said seatya float actuated valve adapted whenopen to drainfluid from said fluid pressure actuated means faster-thanit may be renewed through said leakage opening, and a float associatedwith saidfloat ractuated valve movable upward or downward to actuatesaidj float actuated valveandoperative upon a predetermined upwardor.downward= movement to 1 open said float. actuated valve, therebytoallow said main valve closing disc to be disengaged. 1

from said mainvalve seat.-

3. A float controlled. valve mechanism which comprises a housing, apartition extending across the inside'o'f said housing,- a diaphragmextending across the inside" of said housing above'said partition andenclosing a pressure tight chamber between sai'd'partition and saiddiaphragm, a main valve closingdisc carried on the upper side of saiddiaphragm; a valve seat in said housing adapted to be closed by saiddisc when said diaphragm israised "by' pressure 'within said chamber,the area'within said'valve seat being materially less than'th'eareaof'diaphragm ex-' posed to said chamber; "a leakage passageway connectingthe-spacewithin said seat to said chamber, a float operated valveadapted when open to drain fluid under pressure from said chamber fasterthan-it may be replenished through said leakage opening, and a float,adapted in a medial position to' maintain said float operated valveclosed, and in positions above andbelow said medial position to'keepsaid float'operated valve open.

DAVID SAMIRAN.

REFERENCES CITED The following references are of record'in the.

file of this patent:

UNITED- STATES PATENTS

